Enabling a timeout feature

Question

Hello!
I'm working on a program that will be used for testing new components. You do this by creating a test case that consists of one or more test commands. A test command might be, for example, a database query or a call to an ejb. Now, as one of the last things to do, I'm supposed to implement a timeout feature using threads. After a specified amount of time, the test command should time out. Since there are at least 4 different test commands, I'd like to find a general way of stopping a thread.
Using Thread.stop() seems to stop the tread but I see it's deprecated. But does it really matter? It's been deprecated for quite a while and hasn't been removed in jdk 1.4. And dead-locks shouldn't be a problem since there's only one thread running at a time.
But I guess Thread.stop() won't stop a thread while it's waiting for a inputstream.read() (or so I've understood after reading a few posts here). So perhaps there is no general way of stopping a test command.
Running a test command involves three steps:
1. Collecting input
2. Execute the command - might take too much time
3. Validating the output - might take too much time
Step 2 involves sending a message to a server and waiting for a response. Both steps 2 & 3 must be stoppable.
Any thoughts would be appreciated.
Best regards,
Pelle Poluha

Answer 1

As you rightly understand, there's no generic way of stopping threads. You should have an application-specific logic in order to stop a blocking thread. In your case where you read from inputstream, you may try using something like this:
Thread's run method:
public void run(){
    while(running) {
         if ((int n = inputstream.available()) > 0) {
              // create a buffer which can hold the available         
              // data and read only somany bytes. This
              // approach has lower risk of blocking.
              byte[] buf = new byte[n];
              inputstream.read(buf);
         } // end if
     } // end while
     inputstream.close();
} // end runFrom the place you want to stop this thread, make that boolean variable running to false. Make sure running variable is common. This might solve your one problem.
If in case your application blocks on sockets, you would have to make those sockets return some dummy data/EOF/exception.
I too wonder why stop method is still there in 1.4. Hopefully one day we'll have a better and generic way to stop threads.
regds,
CA